code: def forward(self, a, b, c):
      return a + b + c
  
file_path: chainer/tests/chainermn_tests/extensions_tests/test_multi_node_evaluator.py
imports: import chainer
  import chainer.testing
  from chainer.datasets import TupleDataset
  from chainer.iterators import SerialIterator
  from chainermn import create_communicator
  from chainermn.extensions import GenericMultiNodeEvaluator
label_desc: Use image node_id 1 for calling the ExampleModel obj's underlying member method code with example usage: obj.forward(a, b, c) and returns: unknown